1. Field of the Invention
The present invention relates to cooling devices, and more particularly, to a cooling device for cooling liquid such as oil, water and the like.
2. Description of the Background Art
Conventionally, cooling devices for cooling liquids using various cooling systems have been invented. As an example of such a cooling device for cooling liquid, a cooling device for engine oil i.e. an oil cooler, for example installed in an automobile and the like will be described with reference to FIGS. 9 to 11. FIG. 9 is a plan view showing a conventional oil cooler. FIG. 10 is an internal plan view of the oil cooler shown in FIG. 9. FIG. 11 is a front view of the oil cooler shown in FIG. 9.
Referring to FIGS. 9 and 11, a conventional oil cooler 50 includes an oil inlet 51 through which engine oil is supplied, an oil outlet 52 through which the engine oil cooled by oil cooler 50 is discharged, a water inlet 53 through which cooling water for cooling the engine oil is supplied, and a water outlet 54 through which the cooling water is discharged after cooling the engine oil.
Next, referring to FIG. 10, by an internal structure of the conventional oil cooler 50 will be described. Referring to FIG. 10, a plurality of panels 55 are disposed approximately parallel with each other and with a predetermined space from each other in the interior of conventional oil cooler 50 so that a plurality of passages 56 for engine oil passing through the oil cooler 50 are defined. Passages 56 for engine oil and passages 57 for cooling water are defined by panels 55.
The engine oil supplied through oil inlet 51 is discharged from oil outlet 52 after passing passages 56 for engine oil defined by the plurality of panels 55. Passage 57 for cooling water are provided adjacent to passages 56 for engine oil. Because of this structure, the engine oil is cooled by the cooling water when it passes through passages 56 for engine oil.
The cooling water is introduced into oil cooler 50 from water inlet 53 to be discharged out of oil cooler 50 from water outlet 54 after passing through passages 57 for cooling water. When the cooling water passes through passages 57 by cooling water, it removes heat from the engine oil passing through passages 56 for engine oil provided adjacent to passages 57 for cooling water to cool the engine oil.
As described above, since the engine oil is cooled by the cooling water introduced into passages 57 for cooling water, it is preferred that a number for passages 57 of cooling water and a number of passages 56 for engine oil are provided in order to cool the engine oil more effectively. Provision of many passages 57 and passages 56 makes it possible to remove heat from the engine oil more effectively.
However, oil cooler 50 of a conventional type having the above-described structure has the following problems.
From the view point of improvement of performance such as fuel costs, automobiles lighter in weight are preferable. Therefore, it is necessary to make lighter components such as an oil cooler and the like provided as equipment on the automobile. However, as described above, in an oil cooler 50 of a conventional type, it is necessary to provide more panels 55 in order to enhance cooling efficiency.
As described above, by increasing the number of panels 55, oil cooler 50 is made larger, causing a problem that the weight is accordingly larger. For an automobile belonging to the formula 1 type, for example, it is very important to make the automobile lighter in weight. For an automobile of such a type, it is extremely disadvantageous to have components larger in weight.
In order to prevent the device from being made larger, there is one method considered in which the width of passages 57 for cooling water and passages 56 for engine oil defined by panels 55 is made smaller. However, this method brings about a smaller internal structure of oil cooler 50, whereby processing becomes difficult and precision of processing is lowered. As a result, a defect such as a gap occurs in the passage, and there is a high possibility that the engine oil and the cooling water are mixed with each other.
Furthermore, in order to introduce the cooling water into oil cooler 50, it is necessary to have a pump for supplying the cooling water. Therefore, it is necessary to have a space for the pump for supplying the cooling water in a limited space in the automobile. In addition to this, there may be a problem that, when the automobile rounds a curve, circulation of the cooling water is degraded by the centrifugal force.